In the context of the Internet, as the techniques for transmitting audio and video streams without interruption, conventionally developed is a bandwidth control technique (e.g., S. Floyd et al., “Link-sharing and Resource Management Models for Packet Networks”, IEEE/ACM Trans. on Networking, Vol. 3, No. 4, pp. 365–386, August 1995). Also developed as a technique for implementing a high-speed acquirement of Web documents is a caching technique (e.g., L. Rizzo et al., “Replacement Policies for a Proxy Cache”, IEEE/ACM Trans. On Networking, Vol. 8, No. 2, pp. 158–170, April 2000.). Even with these techniques, a plurality of terminals, which share transmission bandwidth on the Internet, have encountered a problem of deterioration in transmission quality caused by the occurrence of congestion in the network.
In order to implement comfortable access to outside home by sharing a transmission bandwidth among a plurality of terminals for home use, such a technique is required of a repeater, typified by a gateway, that can make use of bandwidth in an efficient manner. Gateways interconnect transmission paths having different transmission bandwidths, thus developing a gap in transmission bandwidth. Suppose a narrower bandwidth is available to the transmission path for use outside home than to the transmission path for home use. In this case, since the bandwidth that can be used at home is restricted to a narrower transmission bandwidth, it is difficult to use an application that makes use of the transmission path of a wider bandwidth for home use.